Abstract TP8: FLAIR Positive and Susceptibility Vessel Sign on T2* Weighted Image did not Associate With Poor Outcome in Acute Ischemic Stroke Patients Treated With Thrombectomy at 6 to 24 Hours

Background: Two randomized controlled trials published in 2018 showed the effect of thrombectomy for acute ischemic stroke more than 6 hours after onset. It is reported that hyperintense lesions on fluid-attenuated inversion recovery (FLAIR positive) and susceptibility vessel sign (SVS) on T2*WI are associated with poor outcome (PO) in patients treated with rt-PA thrombolysis within 4.5 hours in acute ischemic stroke. However, it is not clear that FLAIR positive and SVS on T2*WI are associated with PO in patients treated with mechanical thrombectomy at 6 to 24 hours after the onset. Method: We enrolled 72 consecutive patients treated with mechanical thrombectomy for acute ischemic stroke at 6 to 24 hours after the onset from April 2011 to June 2018. We retrospectively compared PO (a score of 3 to 6 on the modified Rankin Scale at 90 days) group (n=38) with good outcome (GO, a score of 0, 1, or 2 on the modified Rankin Scale at 90 days) group (n=34) and examined what was the predictor of PO. Result: FLAIR positive (41.2% vs 25.8%, P= 0.408) and SVS on T2*WI (32.4 vs 29.0%,P=0.852) were found similarly between both groups. Moreover, there was no significant difference between PO and GO groups in age (75.7 years old vs 69.4 years old, P= 0.062), stroke subtypes (P= 0.129), occlusion site (P= 0.682), DWI-ASPECTS (9 vs 8, P= 0.086), other risk factors. National Institutes of Health Stroke Scale (NIHSS) at admission was higher in PO group than GO group (17 vs 12, P = 0.047). The duration from onset to recanalization (O2R) was significantly longer in PO group than in GO group (765 min vs 631 min, P=0.043), and the median Thrombolysis In Cerebral Infarction (TICI) grade was significantly lower in PO group (P Conclusion: FLAIR positive and SVS on T2*WI did not associate with poor outcome in patients treated with thrombectomy at 6 to 24 hours.